AJP - Regulatory, Integrative and Comparative Physiology, Vol 241, Issue 3 163-R166, Copyright © 1981 by American Physiological Society
Right atrium mediates a vasomotor reflex
R. F. Munzner, D. G. Ward and D. S. Gann
To examine the role of right atrial receptors in mediating reflex vascular
responses we measured, in cats anesthetized with chloralose/urethan,
changes in mean arterial pressure (MAP) in response to volume pulsation of
the right atrium (+/- 1 ml, 1 Hz). Changes in MAP were measured 1) with
pressure in the carotid arteries normal and vagus nerves intact: right
atrial pulsation led to a very small and transient fall in MAP; 2) with
pressure in the carotid arteries at 75 mmHg and the vagus nerves intact:
right atrial pulsation led to a larger and sustained fall in MAP; 3) with
pressure in the carotid arteries at 75 mmHg and the vagus nerves cooled or
sectioned bilaterally: right atrial pulsation of the right atrium led only
to a very small and transient fall in MAP. These data suggest strongly that
signals from right atrial receptors traveling in the vagus nerves mediate a
reflex change in MAP that is normally masked by signals from carotid
receptors.
